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Diffstat (limited to 'boost/detail/dynamic_bitset.hpp')
| -rw-r--r-- | boost/detail/dynamic_bitset.hpp | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/boost/detail/dynamic_bitset.hpp b/boost/detail/dynamic_bitset.hpp new file mode 100644 index 0000000000..281aa55cd6 --- /dev/null +++ b/boost/detail/dynamic_bitset.hpp @@ -0,0 +1,229 @@ +// ----------------------------------------------------------- +// +// Copyright (c) 2001-2002 Chuck Allison and Jeremy Siek +// Copyright (c) 2003-2006, 2008 Gennaro Prota +// +// Distributed under the Boost Software License, Version 1.0. +// (See accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt) +// +// ----------------------------------------------------------- + +#ifndef BOOST_DETAIL_DYNAMIC_BITSET_HPP +#define BOOST_DETAIL_DYNAMIC_BITSET_HPP + +#include <cstddef> +#include "boost/config.hpp" +#include "boost/detail/workaround.hpp" + + +namespace boost { + + namespace detail { + namespace dynamic_bitset_impl { + + // Gives (read-)access to the object representation + // of an object of type T (3.9p4). CANNOT be used + // on a base sub-object + // + template <typename T> + inline const unsigned char * object_representation (T* p) + { + return static_cast<const unsigned char *>(static_cast<const void *>(p)); + } + + template<typename T, int amount, int width /* = default */> + struct shifter + { + static void left_shift(T & v) { + amount >= width ? (v = 0) + : (v >>= BOOST_DYNAMIC_BITSET_WRAP_CONSTANT(amount)); + } + }; + + // ------- count function implementation -------------- + + typedef unsigned char byte_type; + + // These two entities + // + // enum mode { access_by_bytes, access_by_blocks }; + // template <mode> struct mode_to_type {}; + // + // were removed, since the regression logs (as of 24 Aug 2008) + // showed that several compilers had troubles with recognizing + // + // const mode m = access_by_bytes + // + // as a constant expression + // + // * So, we'll use bool, instead of enum *. + // + template <bool value> + struct value_to_type + { + value_to_type() {} + }; + const bool access_by_bytes = true; + const bool access_by_blocks = false; + + + // the table: wrapped in a class template, so + // that it is only instantiated if/when needed + // + template <bool dummy_name = true> + struct count_table { static const byte_type table[]; }; + + template <> + struct count_table<false> { /* no table */ }; + + + const unsigned int table_width = 8; + template <bool b> + const byte_type count_table<b>::table[] = + { + // Automatically generated by GPTableGen.exe v.1.0 + // + 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, + 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, + 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, + 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, + 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, + 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, + 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, + 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8 + }; + + + // overload for access by bytes + // + + template <typename Iterator> + inline std::size_t do_count(Iterator first, std::size_t length, + int /*dummy param*/, + value_to_type<access_by_bytes>* ) + { + std::size_t num = 0; + if (length) + { + const byte_type * p = object_representation(&*first); + length *= sizeof(*first); + + do { + num += count_table<>::table[*p]; + ++p; + --length; + + } while (length); + } + + return num; + } + + + // overload for access by blocks + // + template <typename Iterator, typename ValueType> + inline std::size_t do_count(Iterator first, std::size_t length, ValueType, + value_to_type<access_by_blocks>*) + { + std::size_t num = 0; + while (length){ + + ValueType value = *first; + while (value) { + num += count_table<>::table[value & ((1u<<table_width) - 1)]; + value >>= table_width; + } + + ++first; + --length; + } + + return num; + } + + // ------------------------------------------------------- + + + // Some library implementations simply return a dummy + // value such as + // + // size_type(-1) / sizeof(T) + // + // from vector<>::max_size. This tries to get more + // meaningful info. + // + template <typename T> + typename T::size_type vector_max_size_workaround(const T & v) { + + typedef typename T::allocator_type allocator_type; + + const typename allocator_type::size_type alloc_max = + v.get_allocator().max_size(); + const typename T::size_type container_max = v.max_size(); + + return alloc_max < container_max? + alloc_max : + container_max; + } + + // for static_asserts + template <typename T> + struct allowed_block_type { + enum { value = T(-1) > 0 }; // ensure T has no sign + }; + + template <> + struct allowed_block_type<bool> { + enum { value = false }; + }; + + + template <typename T> + struct is_numeric { + enum { value = false }; + }; + +# define BOOST_dynamic_bitset_is_numeric(x) \ + template<> \ + struct is_numeric< x > { \ + enum { value = true }; \ + } /**/ + + BOOST_dynamic_bitset_is_numeric(bool); + BOOST_dynamic_bitset_is_numeric(char); + +#if !defined(BOOST_NO_INTRINSIC_WCHAR_T) + BOOST_dynamic_bitset_is_numeric(wchar_t); +#endif + + BOOST_dynamic_bitset_is_numeric(signed char); + BOOST_dynamic_bitset_is_numeric(short int); + BOOST_dynamic_bitset_is_numeric(int); + BOOST_dynamic_bitset_is_numeric(long int); + + BOOST_dynamic_bitset_is_numeric(unsigned char); + BOOST_dynamic_bitset_is_numeric(unsigned short); + BOOST_dynamic_bitset_is_numeric(unsigned int); + BOOST_dynamic_bitset_is_numeric(unsigned long); + +#if defined(BOOST_HAS_LONG_LONG) + BOOST_dynamic_bitset_is_numeric(::boost::long_long_type); + BOOST_dynamic_bitset_is_numeric(::boost::ulong_long_type); +#endif + + // intentionally omitted + //BOOST_dynamic_bitset_is_numeric(float); + //BOOST_dynamic_bitset_is_numeric(double); + //BOOST_dynamic_bitset_is_numeric(long double); + +#undef BOOST_dynamic_bitset_is_numeric + + } // dynamic_bitset_impl + } // namespace detail + +} // namespace boost + +#endif // include guard + |